We studied 12 candidate genes that are implicated in the aetiology of breast cancer (Table 1): BRCA1, BRCA2, C1qA, CCND3, EMSY, GPX1, GPX4, MLH3, MTHFR, NBS1, TP53 and TRXR2 [28-31]. The gene discussed is MTHFR; the disease is breast carcinoma.